In Hawaii, as in many other states, tourism is a large industry. Most hotel jobs require little education or training, and hotels employ large numbers of low SES persons and immigrants. Hawaii, with the world's most ethnically diverse population, has high rates of obesity and diabetes, particularly among those of Polynesian ancestry (about 20-22% of the population). This study is a comprehensive lifestyle change program delivered through worksites in partnership with a large health care system. The goal is to increase physical activity, improve diet, and reduce obesity of hotel employees. Forty hotels in Hawaii employing 6,000-7,000 persons will be pair matched. One member of each pair will be assigned to intervention, one.to control. All employees will be assessed for BMI and complete a questionnaire on lifestyle habits, stage of change, and attitudes toward weight. A subgroup of 800 persons (half in each group) will complete additional physical and questionnaire assessments. Assessments will be repeated 12 and 24 months later. Intervention hotels will receive an intervention that includes 1) environmental changes to support lifestyle change and obesity control, 2) worksite-based groups that will offer state of-the art behavioral interventions, and 3) after hours groups and case management available to those with a BMI >30 who are committed to losing weight. Interventions incorporate all elements that produce sustained weight loss and an innovative decision tutorial based on decision theory. The primary outcome is change in BMI among employees of intervention versus control hotels. Secondary outcomes address effects of the intervention on ethnic and occupational subgroups, stage of change and other issues. We will conduct an economic analysis of the interventions and and actively disseminate the program in year 04 if it is effective. We have also applied to carry out the Coordinating Function for the group of sites that receives awards under this RFA.